Noticed that my Yamaha c4 preamp supports various loads with nos. like 33,47,68,100 and nos. like 100pf,150pf,220pf,330pf and 470pf. Question,what do these numbers mean? Some cartridges say 150-400pf what should I choose? Presently am using a shure M44 and it says 450pf should I put setting to 330pf or 470pf? Thanks for any advise.

Edwin, the numbers 33, 47, 68, and 100 are cartridge impedances/resistances in kilohms, and the others are cartridge capacitances in picofarads. All cartridges work best when matched up to their optimum loads, meaning their sound will be closest to what the designers wanted when the cartridge was on their drawing board.

If Shure says their capacitance is 450pF, then use 470pF. Close enough for government work. That's what most cartridges use anyhow. If the manufacturer says anything in a range is acceptable, that's when you get to pick any of the available settings on your Yammi and settle on what YOU think sounds the best.

Likewise, 47kilohms is what most cartridges use for input impedance. If that's what Shure designed it for, then try that setting first on the Yamaha. (That's what my Ortofon uses, 47k) If you want to try any of the other settings, that's fine too. If you find one that sounds better to you than a factory-suggested setting, go ahead and use it. You won't break anything.

Hope this helps. If anyone else has a different outlook, I'm sure they'll chime in:)

Tom

...47K was the "standard" for MM cartridge impedances. The capaticatance may vary somewhat but a mismatch isn't a drastic showstopper. Some might even prefer a slight mismatch there, except when trying to extract CD-4 quad sound. Then, a major mismatch could wipe out the two surround channels, which extend up to about 45k on the vinyl.

You can try different configurations. It won't hurt anything. Set it for the most pleasing sound if you don't know the specifications for your cartridge.
Ron